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A348776 The numbers >= 2 with 3 repeated. 1
2, 3, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
This sequence, 2, 3, 3, 4, 5, 6, 7, ..., gives the stable range of the polynomial rings Z, Z[x_1], Z[x_1, x_2], Z[x_1, x_2, x_3], ...
A note on terminology: "stable range" and "stable rank" are the same thing. In the English-speaking world, people have always used the term "stable range", which was what Bass had invented in the early '60s. When Russian workers wrote on this theme, of course they used a Russian translation of the term "stable range". When the term was translated back into English, it became "stable rank"! - T. Y. Lam, Nov 07 2021
REFERENCES
T. Y. Lam, Excursions in Ring Theory, in preparation, 2021. See Section 24.
LINKS
F. Grunewald, J. Mennicke, and L. Vaserstein, On the groups SL_2(Z[x]) and SL_2(k[x, y]), Israel J. Math., 86(1-3):157-193, 1994.
Luc Guyot, The stable rank of Z[x] is 3, arXiv:2111.02965 [math.AC], November 2021.
L. N. Vaseršteĭn and Andrey Aleksandrovich Suslin, Serre's Problem on Projective Modules over Polynomial Rings, and Algebraic K-theory, Mathematics of the USSR-Izvestiya 10.5 (1976): 937 (Russian version).
FORMULA
a(n) = n for n >= 3.
From Chai Wah Wu, Aug 09 2022: (Start)
a(n) = 2*a(n-1) - a(n-2) for n > 4.
G.f.: x*(x^3 - x^2 - x + 2)/(x - 1)^2. (End)
PROG
(Python)
def A348776(n): return n+int(n<3) # Chai Wah Wu, Aug 09 2022
CROSSREFS
Sequence in context: A257682 A029928 A101788 * A024698 A011883 A034886
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Nov 07 2021, following a suggestion from L. Guyot and T. Y. Lam.
STATUS
approved

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Last modified February 23 11:40 EST 2024. Contains 370283 sequences. (Running on oeis4.)